Influence of hydrophilic polymers on mechanical property and wound recovery of hybrid bilayer wound dressing system for delivering thermally unstable probiotic.

In this study, a novel hybrid bilayer wound dressing (HBD) has been developed for delivering a thermally unstable probiotic, Lactobacillus brevis. The HBD was composed of two layer, a hydrocolloid layer and a Lactobacillus brevis-loaded hydrogel layer as a block supporter and drug carrier, respectively. Moreover, various probiotic-loaded hydrogel layers in HBD were prepared with polyvinyl alcohol (PVA) and numerous hydrophilic polymers via a freezing and thawing method, and their mechanical property, release and wound recovery were assessed.

Diastereoselective Construction of -2-Alkyl-6-aryl-3,6-dihydro-2-pyrans via Dehydrogenative Cycloetherification Promoted by DDQ.

A diastereoselective synthesis of -2-alkyl-6-aryl-3,6-dihydro-2-pyrans has been described. Dehydrogenative cycloetherification of ()-(±)-1-aryl-5-hydroxy-1-alkenes promoted by DDQ proceeded cleanly via 6- cyclization to afford -2-alkyl-6-aryl-3,6-dihydro-2-pyrans (32 examples) in good yield (up to 89%) and with moderate to excellent diastereoselectivity (up to 99:1). The synthetic utility of the method was illustrated by the second total synthesis of (±)-(2,6)-3,4-dehydro-1,7-bis(4-hydroxy phenyl)-4'-de--methyl centrolobine and a total synthesis of (±)-centrolobine.

Direct and Efficient C(sp)-H Functionalization of -Acyl/Sulfonyl Tetrahydroisoquinolines (THIQs) With Electron-Rich Nucleophiles via 2,3-Dichloro-5,6-Dicyano-1,4-Benzoquinone (DDQ) Oxidation.

A highly efficient metal-free oxidative direct C(sp)-H functionalization of -acyl/sulfonyl 1,2,3,4-tetrahydroisoquinolines (THIQs) with a wide range of electron-rich nucleophiles was accomplished under mild conditions through oxidation with DDQ and subsequent trapping of the resulting reactive and stable -acyl/sulfonyl iminium ions. The synthetic utility of this method was illustrated by a concise and efficient total synthesis of (±)-benzo[]quinolizidine () in 3 steps from the known -Cbz 1,2,3,4-THIQ .

Lewis Acid-Promoted Regio- and Diastereoselective Cross-Coupling of Aryl-Substituted 1,2-Diols and Boronic Acids.

A Lewis acid-promoted highly regio- and diastereoselective C(sp)-C(sp) cross-coupling reaction between unprotected aryl-substituted 1,2-diols and styryl-, aryl-, heteroaryl-, and polyarylboronic acids has been developed in a one-pot procedure. The regioselective opening of aryl-substituted cyclic boronic esters promoted by a Lewis acid followed by subsequent intramolecular 1,4-transfer of the carbon ligand from boron to a resonance-stabilized benzylic carbenium ion minimizing the allylic 1,3-strain in a stereoselective fashion led to the corresponding α-substituted syn-phenylethyl alcohols. The synthetic utility of the method was illustrated by a short and efficient enantioselective synthesis of cherylline diethyl ether (-)-16.

DDQ-Promoted Mild and Efficient Metal-Free Oxidative α-Cyanation of -Acyl/Sulfonyl 1,2,3,4-Tetrahydroisoquinolines.

A mild and highly efficient metal-free oxidative α-cyanation of -acyl/sulfonyl 1,2,3,4-tetrahydroisoquinolines (THIQs) has been accomplished at an ambient temperature via DDQ oxidation and subsequent trapping of -acyl/sulfonyl iminium ions with (-Bu)₃SnCN. Employing readily removable -acyl/sulfonyl groups as protecting groups rather than -aryl ones enables a wide range of applications in natural product synthesis. The synthetic utility of the method was illustrated using a short and efficient formal total synthesis of (±)-calycotomine in three steps.